Liquid crystal display is a display device that is currently widely used, and has a series of advantages such as high color gamut, thinness and light weight, fast response, etc. There are mature technologies for the liquid crystal display in terms of theoretical research and practice process. Display principle of the current liquid crystal display is to perform gray display by using liquid crystal to modulate polarized light. A polarization sheet is a necessary component of a liquid crystal display device. However, attaching polarization sheets respectively to a light incident side and a light emitting side of a liquid crystal display panel, on one hand, will cause an increased cost of the liquid crystal display panel, and on the other hand, will lead to loss of light efficiency, where the polarization sheets may cause loss of up to 50% or more of light efficiency of the liquid crystal display panel.